Syntactic foams containing hollow ceramic microspheres are used for insulation in a variety of applications due in part to their low thermal conductivities. For example, syntactic foams are used in wet insulation applications (i.e., insulation that is exposed to sea water) for off-shore oil pipelines or flowlines. In these pipelines or flowlines, the temperature of the surrounding water can be less than 10° C., which can lead to extensive heat loss from the oil present in the pipe. Such heat loss can result in a reduction of the flow of oil due to an increase in viscosity of the oil and/or precipitation of paraffins and/or asphaltenes present in the oil. Some wet insulation systems combine unfilled polymer layers with syntactic foam layers in order to maintain the temperature of the oil in the pipelines or flowlines as close to the production temperature as possible. However, unfilled polymer layers typically exhibit higher volume shrinkage and/or have higher coefficients of thermal expansion than typical syntactic foams, which could cause stresses within or between the insulation layers. One solution to the problem of shrinkage in an unfilled polypropylene insulation layer is to add solid glass beads to the polypropylene; however, this composition tends to have excessive thermal conductivity. There is a need for alternative syntactic foam insulation systems to meet the demands of severe environments, (e.g., off-shore oil pipelines or flowlines).